In recent years, network technologies advance rapidly, and thus the chance and demand of using a network become increasingly higher. To meet the requirements of transmitting messages over the network, network manufacturers provide different technologies and standards to support different objectives and environments. As to the different network transmission standards, a solution of transmitting messages of different transmission standards via a network is an important subject.
In general, a conventional network requires a network transmission line for the transmission of messages, and sometimes requires two or more transmission protocol standards to transmit messages to meet the requirements of different purposes. In other words, two or more types of cables are sometimes needed, and thus incurring an additional cost of the cables for constructing the network infrastructure. To transmit messages of two transmission protocol standards among different networks, a network protocol converting device is used and thus incurs an additional cost. As technology advances, new network protocol standards are introduced, and finding a way of effectively lowering the cost for constructing the infrastructure and flexibly updating a transmission protocol standard on the existing cable structure demands immediate attentions and feasible solutions.
In the prior art, messages are transmitted via a network according to different transmission standards such as an IP or non-IP transmission standard including Ethernet, X-10, control area network (CAN), RS-485, 1394, universal serial bus (USB) and media oriented systems transport (MOST), etc. In an example of the application, the messages of two different transmission protocols and standards are transmitted among different networks. In the present existing method, an appropriate protocol converting device is installed among networks of different transmission protocols and standards for converting the messages. However, it is necessary to install a plurality of protocol converting devices of several different transmission protocols and standards for transmitting the messages in order to meet the requirements of an increasing larger network structure and more updated network protocol standards, and such architecture becomes more complicated and incurs a higher cost.
In the prior art, a network connecting device uses a gateway to connect two networks of different protocols, and a typical gateway adopts a combination of software and hardware for interpreting the protocol, and then transmits the data from a network to another network. The network architecture is connected by a gateway in the prior art, and the transmission of the messages via independent networks of different protocols requires the interpretation by the gateway.
In the prior art, the mechanisms used for accessing messages of different types of protocols transmitted through a single medium includes polling, token passing, carrier sense multiple access (CSMA) and time division multiple access (TDMA). In the conventional polling mechanism, a master station periodically inquires a slave station for controlling the priority of the network media of the slave station. In the conventional token passing mechanism, a token ring at a network node of a token-ring network is provided for processing. The determination of a protocol used for the accessing procedure in the conventional CSMA mechanism is determined by the competition among the stations, and each station monitors the network condition to determine whether or not the network is in an idle state. If the network is at an idle state, the station will start transmitting signals after a predetermined time period. If a conflict exists, the station will continue monitoring the network condition and wait for the correct time for transmitting the signals. In the conventional TDMA mechanism, a network master station issues and broadcast a message to a plurality of frames synchronously, such that the time slot of each frame is synchronized, and the time slot for transmitting the signals is assigned, and each slave station receives a message synchronization signal and uses the signal for specifying the time slot for the signal transmission.
A method and an apparatus of transmitting data via a multi-protocol single-medium network data in accordance with the present invention adopt a TDMA multi-protocol access mechanism. U.S. Pat. No. 6,831,913 entitled “Method of identifying network layer PDU” and U.S. Pat. Application No. 2006/0153237 entitled “Communication system with improved medium access control sub-layer” did not teach a common method of accessing messages of different protocols, but both patents store different types of protocols in seven network layers of the OSI network. U.S. Pat. Application No. 2006/0198387 entitled “Reserving time periods for communication on power line networks” uses a CSMA mechanism which is different from the method using the TDMA mechanism in accordance with the present invention. U.S. Pat. Application No. 2004/0136396 entitled “Contention-free access intervals on a CSMA network”, U.S. Pat. Application No. 2005/0114489 entitled “Medium access control layer that encapsulates data from a plurality of received data units into a plurality of independently transmittable blocks” and U.S. Pat. Application No. 2005/0169296 entitled “Temporary priority promotion for network communications in which access to a shared medium depends on a priority level” adopt the CSMA protocol mechanism. Unlike the protocol stack disclosed in the present invention, these patented inventions use a protocol stack on a physical layer.
Since the method and apparatus of transmitting data via a multi-protocol single-medium network in accordance with the invention adopt a TDMA mechanism, the prior art single medium for transmitting different network services includes MOST, and the prior art TDMA protocol includes FlexRay, TTP/C and Byteflight, etc. The MOST of the same packet includes control messages, synchronous messages and asynchronous messages used for providing several types of network transmission services, but its shock-proof mechanism adopts CSMA, and FlexRay uses different time slots for storing different transmitting messages for transmitting data, and the packet comes with a fixed length which is a variable packet length in this invention, and the protocol in each packet may vary. Although the TTP/C uses the same TDMA protocol, yet the packets of different protocols transmitted in the time slots are different.
In view of the foregoing shortcomings of the prior art, the present invention provides a method and an apparatus of transmitting data via a multi-protocol single-medium network for transmitting messages of different transmission protocols through a single medium, wherein different network devices can select an appropriate transmission protocol for receiving the messages, and transmitting the messages to another network device through the single medium.